In general, a lot of structures such as signal lamps, traffic signs and the like are positioned on a road.
These structures are made of various materials such as wood, synthetic resins, metal, etc.
Initially, these structures were mainly made of wood. However, structures fabricated of wood are very susceptible to humidity.
As an alternative to a material for such road structures, synthetic wood has been proposed because it provides natural texture and resists humidity.
However, it is difficult to apply general synthetic wood to a traffic light and similar structures, which have to be recognized at night, since general synthetic wood has no light reflecting function.